The expression of foreign genes in various cell types has become a commonplace occurrence in the field of biotechnology. The expression of the foreign, or heterologous, gene is performed by the transcription of the genetic information in the gene from DNA to RNA. The RNA is then translated into the protein for which the gene encodes.
In transcription, the RNA is synthesized using the DNA of the gene for a template. The RNA is synthesized by a reaction catalyzed by RNA polymerases. The RNA polymerase binds to a particular molecular site on the DNA to initiate the transcription process. This site to which the RNA polymerase binds is known as the promoter.
Therefore, in order to express heterologous genes in foreign cells, the genes must be under the control of a promoter. Although numerous promoters for expressing foreign genes have been taught in the literature, these promoters have generally failed to function when used to express genes within myeloid cells. Therefore, a need exists for promoters which may be used to express genes within such cells.
Integrins are a large family of cell surface glycoproteins that are heterodimers comprised of α and β chain subunits. The promoters of integrins are of special interest as these promoters may be used to express genes in a myeloid-specific manner. This is especially useful, as typical promoters which are used in genetic research, such as retroviral promoters, become repressed after being introduced into myeloid cells.
Genes linked to myeloid specific promoters may be used in a wide variety of applications. These applications include use in the development of cancer vaccines, as well as being used for screening compounds for their effect on myeloid cell specific gene expression.
A need therefore remains for the identification and isolation of myeloid cell specific promoters.